超临界CO2中苯乙烯RAFT分散聚合

以末端带有三硫代碳酸酯的聚二甲基硅氧烷(PDMS-TTC)为大分子链转移剂,在超临界CO2中通过苯乙烯的可逆加成-断裂链转移(RAFT)聚合制备了聚二甲基硅氧烷-b-聚苯乙烯(PDMS-b-PS)嵌段共聚物,对聚合反应动力学以及产物的组成、分子量和形貌等进行了表征.由于PDMS链段可溶于超临界CO2而PS链段不溶,因此在超临界CO2中制备PDMS-b-PS嵌段共聚物的过程是以嵌段共聚物自身作为分散稳定剂的RAFT分散聚合,产物为粒径较均一的球形颗粒.

RAFT Dispersion Polymerization of Styrene in Supercritical CO2

A block copolymer polydimethyllsiloxane-b-polystyrene(PDMS-b-PS) was prepared by reversible addition fragmentation chain transfer(RAFT) polymerization of styrene in supercritical CO2(scCO2), using polydimethylsiloxane terminated by trithiocarbonate(PDMS-TTC) as a macromolecular chain transfer agent. The polymerization reaction kinetics, composition, molecular weight and morphology of the product were investigated by FTIR, 1H NMR, GPC and SEM. Since PDMS chain segments could be dissolved in scCO2 while PS segments were insoluble, the polymerization was a RAFT dispersion polymerization using the block copolymer itself as a dispersion stabilizer, and the resultant products were spherical particles with more uniform particle size, which was proved by SEM characterization.